start there and add more or less depending on the answers to the following.
how much flex do you really want ?
(try to quantify it: inches, lbs/in, 2x your old board, etc)
your weight?
core thickness?
length and width?
type of glass (plain weave, biax, unidirectional)?
epoxy (yes)
carbon (no)

yahoo boardbuilders group has alot of specific examples to copy.
-bill